apb_vip_user_manual.pdf

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SysWip APB Verification IP User Manual

SysWipAlternative Verification

AMBA Peripheral Bus Verification IP

User ManualRelease 1.0

Page 1 of 18 Release 1.0


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2. APB Master

The APB Master Verification IP(VIP) is generating transactions on the APB bus. It can also beconsidered as a AHB/APB bridge replacement used in real designs. Please note that it does not have

AHB/APB bridge functionality and can only be considered bridge replacement from APB side.

The APB VIP supports only one slave device. For connecting more slaves external decoder is

needed.

Features

The APB Master VIP has the following features:

Configurable data bus width 8, 16 and 32 bits wide

Misaligned transfers

Fixed and random transfer delay insertion

Configurable pready time out

Slave error detection and configurable error messages

Complete data packet transaction read/wite

Bus idle cycle insertion

Address polling

Failed transaction buffer

Configuration Commands

All configuration commands listed bellow have zero cycle execution time and executingimmediately without waiting in the queue.

APB data bus width: Can be set only during APB object creation and cannot be changed

during simulation.

setPreadyTimeOut():

setPollTimeOut():

setDelay():

rndDelayEn():

setErrMsgs():

Data Transfer Commands

Commands marked as a queuedwill be put in the one queue and executed sequentially.

Commands marked as a blocking will block other commands execution until finishing own process.



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writeData(): - queued,

writeWord(): - queued, non blocking

readData(): - queued, blocking

readWord(): - queued, blocking

pollWord(): - queued, blocking

busIdle(): - queued, non blocking

Other Commands

startEnv(): - non queued, blocking, should be called only once for current object

EnvReset(): - non queued, blocking

printFailedTrInfo(): - non queued, non blocking

Commands Description

All commands areABP_m_envclass methods and will be accessed only via class objects.

setPreadyTimeOut()

Syntax

setPreadyTimeOut(timeOutCycles)

Arguments

timeOutCycles: An intvariable that specifypreadysignal waiting clock

cycles.

Description

Sets the maximum number of wait clock cycles forpready signal. After

activatingpselVIP waits valid pready signal. If pready is not valid during

specified clock cycles than VIP will generate error message and continue with

next transaction.

setPollTimeOut()

Syntax

setPollTimeOut(timeOutCycles)

Arguments

timeOutCycles: An intvariable that specify maximum poll clock cycles.

Description

Sets the maximum number of poll clock cycles after which poll task will be

stopped and poll time out error message generated. The only task in APB

Master VIP where poll time out is used ispollWord().



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setDelay()

Syntax setDelay(burstLength, waitCycle)

Arguments

burstLengt: An intvariable that specify the maximum number of transactions

whenpsel signal can be continuously high. For disabling delays put this value

to 0.

waitCycle: An intvariable that specify the number of wait cycles. When

burstLengt is 0 waitCycle willbe ignored.

Description

Sets APB bus timing delay. Which means to set some constraints to psel

signal. The value specified in the burstLengt argument is the maximum

number of transactions whenpsel signal can be continuously high. Then psel

will go to low and wait several clock cycles specified in the waitCycle

argument. For disabling delay call this function with 0 as a first argument.The second one will be ignored.

rndDelayEn()

Syntax

rndDelayEn(minBurst, maxBurst, minWaitCycle, maxWaitCycle) Arguments

minBurst: An intvariable that specify the minimum value for burstLengt

maxBurst: An intvariable that specify the maximum value for burstLengt

minWaitCycle: An intvariable that specify the minimum value for waitCycle

maxWaitCycle: An intvariable that specify the maximum value for waitCycle

Description

Enables APB bus timing random delays. After each transaction new randomvalue will be generated for burstLengt andwaitCycle. The generated random

value will be in the range specified in the function arguments. For disablingrandom delays call setDelay() function with 0 value in the first argument.

setErrMsgs()

Syntax

setErrMsgs(timeOutMsg, slaveErrorMsg)

Arguments

timeOutMsg: A string variable that specify the message which will be

displayed during time out error.



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SlaveErrorMsg: A stringvariable that specify the message which will be

displayed during APB bus slave error detection.

Description

Setspready time out and slave error messages. The message will be displayedin you terminal if corresponding error ocured.

writeWord()

Syntax

writeWord(address, dataWord)

Arguments

address: A 32 bit vector that specifies APB address.

dataWord: A 32 bit vector that specifies APB write data word.

Description

Writes one data word on specified address. If APB data width is less then 32

bits then only corresponding least bits will be used as a data. This task createsonly one write transaction even APB data width is less then 32 bits. So if

data bus is 8 bits and this task was called then only dataWord[7:0] will be

written.

writeData()

Syntax

writeData(address, dataInBuff, addrIncr)

Arguments

address: A 32 bit vector that specifies APB write start address

dataInBuff: A 8 bit vector queue that contains data buffer which should be

transferred

addrIncr: An int variable that specify will address be incremented or noduring complete data buffer transfer. If you don't specify this argument it will

be considered as 1.

Description

Writes complete data buffer on specified address. If addrIncr is 0 then all data

will be written on the same address. It can be useful if you want to write

FIFO. If addrIncr is 1 or not specified then address will be incremented after

each transaction. Incremented value depends on APB data bus width.

readWord()

Syntax

readWord(address, dataWord)

Arguments



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apb_vip/verification_ip/masterfolder.

For usage the following steps should be done:

1. ImportAPB_Mpackage into your test.

Syntax: import APB_M::*;

2. CreateABP_m_envclass object

Syntax: ABP_m_env apb = new(apb_ifc, 4);

Description: apb_ifc is the reference to the APB Master interface instance name.The second argument is APB bus data width in bytes.

3. Start APB Master Environment.

Syntax: apb.startEnv();

This is the all you need for integration. Now you can configure the VIP and start data transfers.



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3. APB Slave

The APB Slave Verification IP does not initiate any transfers and only responds to transactionsinitiated by the APB Master. The APB Slave VIP has a memory element to hold transfer data. It also

has FIFO mode support. In FIFO mode all read data words will be popped from output FIFO and all

write data words will be pushed to input FIFO.

Features

The APB Slave VIP has the following features:

Configurable data bus width 8, 16 and 32 bits wide

Misaligned transfers

Fixed and random delay insertion for pready signal

Configurable poll time out

Slave error insertion for specified addresses

Input and Output FIFO mode

Failed transaction buffer

Configuration Commands

All configuration commands listed bellow have zero cycle execution time and executingimmediately without waiting in the queue.

APB data bus width: Can be set only during APB object creation and cannot be changed

during simulation.

setPollTimeOut():

setDelay():

rndDelayEn():

setFifoAddr():

disableFifoMode():

setSlaveErrAddr():

disableSlaveErr():

Data Processing Commands

Commands marked as a queuedwill be put in the one queue and executed sequentially.

Commands marked as a blocking will block other commands execution until finishing own process.

putWord(): - non blocking

putData(): - non blocking



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getWord(): - non blocking

getData(): - non blocking

pollWord(): - blocking

writeFifoWord(): - non blocking

writeFifo(): - non blocking

readFifoWord(): - blocking

readFifo(): - blocking

Other Commands

startEnv(): - non blocking, should be called only once for current object

fifoReset(): - non blocking

printFailedTrInfo():- non blocking

Commands Description

All commands areABP_s_envclass methods and will be accessed only via class objects.

setPollTimeOut()

Syntax

setPollTimeOut(pollTimeOut)

Arguments

pollTimeOut: An intvariable that specify maximum poll clock cycles.

Description

Sets the maximum number of poll clock cycles after which poll task will be

stopped and poll time out error message generated. If set to zero time out

never occurs.

setDelay()

Syntax

setDelay(preadyDelay)

Arguments

preadyDelay: An intvariable that specify thepready delay cycles after valid

psel signal.

Description

Setspreadytiming delay. After validpsel signal thepready will be delayed

specified amount of clock cycles. If set to zero then thepreadywill alwaysbe valid.

rndDelayEn()



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Syntax

rndDelayEn(minPready, maxPready)

Arguments

minPready: An intvariable that specify the minimum value forpreadyDelay

maxPready: An intvariable that specify the maximum value forpreadyDelay

Description

Enables preadytiming random delays. After each transaction new random

value will be generated forpreadyDelay. The generated random value will be

in the range specified in the function arguments. For disabling random delays

call setDelay() function.

setFifoAddr()

Syntax

setFifoAddr(inFifoAddr, outFifoAddr)

Arguments

inFifoAddr: A32 bit vector that specify the input FIFO address.

outFifoAddr: A32 bit vector that specify the output FIFO address.

Description

Sets addresses for in/out FIFOs and enables FIFO mode. Data word written

by master at inFifoAddr address will be pushed to the input FIFO. Data wordread by master at outFifoAddr address will be popped from the output FIFO.

disableFifoMode()

Syntax

disableFifoMode()

Arguments

non

Description

Disables FIFO mode. Input and output FIFO addresses will be switched to

memory addresses.

setSlaveErrAddr()

Syntax

setSlaveErrAddr(startAddr, endAddr)

Arguments

startAddr: A32 bit vector that specify the start address for slave error space.

endAddr: A32 bit vector that specify the end address for slave error space.



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Description

Sets address space for APB slave error generation. All read or write

transactions initiated by master inside this space will generate slave errorpslverrsignal will be set.

disableSlaveErr()

Syntax

disableSlaveErr()

Arguments

non

Description

Disables APB slave error generation.

putWord()

Syntax

putWord(address, dataWord)

Arguments

address: A 32 bit vector that specifies internal memory address.

dataWord: A 32 bit vector that specifies memory write data word.

Description

Writes one data word to the internal memory on specified address. Data word

size depends on APB data width. It can be 1, 2 and 4 bytes.

putData()

Syntax

putData(address, dataInBuff)

Arguments


dataInBuff: A 8 bit vector queue that contains data buffer which will bewritten to the internal memory. First byte will be written at address.

Description

Writes data buffer to the internal memory starting from specified address.

Each next byte will be written after address increment.

getWord()

Syntax

dataWord = getWord(address)

Arguments



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dataWord: A 32 bit vector that contains memory read data word.

Description

Reads one data word from the internal memory on specified address

getData()

Syntax

getData(startAddr, dataOutBuff, lenght)

Arguments

startAddr: A 32 bit vector that specifies internal memory address.

dataOutBuff: A 8 bit vector queue that contains output data buffer which is

read from the internal memory.

length: Anint variable that specifies the amount of data (in bytes) which will

be read from the internal memory.

Description

Reads length bytes data from the internal memory starting from specifiedaddress and put them into dataOutBuff output buffer.

pollWord()

Syntax

pollWord(pollAddr, pollData)

Arguments

pollAddr: A 32 bit vector that specifies internal memory address.

pollData: A 32 bit vector that contains expected value which will be

compared with memory data.

Description

Reads internal memory specified address until the read data word is equal to

expected pollData data. If time out occurred generates error message and

returns

writeFifoWord()

Syntax

writeFifoWord(dataWord)

Arguments

dataWord: A 32 bit vector data word.

Description

Pushes one data word to the output FIFO.



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printFailedTrInfo()

Syntax

printFailedTrInfo()

Arguments

non, returns number of failed transactions

Description

Displays all time out errors occurred during full simulation time. This

function returns the number of all errors in the buffer. Please not that this

function clears failed transactions buffer.

fifoReset()

Syntax

fifoReset()

Arguments

non

Description

Removes all data words from input and output FIFOs.

Integration and Usage

The APB Slave Verification IP integration into your environment is very easy. Instantiate theapb_s_if interface in you testbench top file and connect interface ports to your DUT. Then during

compilation don't forget to compile apb_s.sv and apb_s_if.sv files located inside the

apb_vip/verification_ip/slave folder.

For usage the following steps should be done:

1. ImportAPB_Spackage into your test.

Syntax: import APB_S::*;

2. CreateABP_s_envclass object

Syntax:ABP_s_env apb = new(apb_ifc, 4); Description: apb_ifc is the reference to the APB Slave interface instance name. The

second argument is APB bus data width in bytes.

3. Start APB Slave Environment

Syntax: apb.startEnv();

This is the all you need for integration. Now you can configure the VIP and start data processing.



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4. Important Tips

In this section some important tips will be described to help you to avoid VIP wrong behavior.

Master Tips

1. CallstartEnv() task as soon as you createdABP_m_envobject before any other commands.

You should call it not more then once for current object.

2. Before using Data Transfer Commands be sure that external hardware reset is done. As

current release does not support external reset detection feature so the best way is to wait

several clock cycles before DUT reset is done.

3. CallprintFailedTrInfo() at the end of the test. As this function will empty error buffer so you

will loss error information calling it in the middle of test. Error messages will be lost in youterminal and it will be difficult to find them after test is done.

4. If you want to use rndDelayEn() function be sure that arguments are correct. The argumentspecifying minimum value should not be more then the argument specifying maximum

value.

5. As all configuration commands are non queued and all Data Transfer Commands are

queued so you will have synchronization issues if want to apply specific configuration to

current transaction. Here one working around for that. Be sure that transaction buffer is

empty. For that you can use readWord() command with dummy address. After this commandchange configuration and then write your data. After writing data you should wait for write

transaction done. Use readWord() command again with dummy address.

Slave Tips

1. CallstartEnv() task as soon as you createdABP_s_envobject before any other commands.

You should call it not more then once for current object. Also be sure that this task was

called before first valid transaction initiated by APB master.

2. CallprintFailedTrInfo() at the end of the test. As this function will empty error buffer so youwill loss error information calling it in the middle of test. Error messages will be lost in you

terminal and it will be difficult to find them after test is done.

3. If you want to use rndDelayEn() function be sure that arguments are correct. The argumentspecifying minimum value should not be more then the argument specifying maximum

value.

4. For the commands which processing words (putWord, getWord and pollWord) the word size

is equal to the APB bus data size. It is set during APB VIP object creation. If data size is 2

bytes (16 bits) then putWord function will write only 2 bytes to the internal memory. First

byte will be written at address provided by argument and the second byte to the incremented

address. When you are using pollWord command be sure that polling data is not more thanallowed maximum value. The allowed maximum value depends on APB bus data size.

When APB bus data size is 8 bits the allowed maximum value is 255, if 16 bits then it is

0xffff.


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